Mechanism for actuating the dipper of a power-operated apparatus



March 24, 1959 2,878,950

J. P. WAITE MECHANISM FOR ACTUATING THE DIPPER OF A POWER-OPERATED APPARATUS Filed July 5, 1955 ATTORNEYS.

United States Patent '()ice MECHANI-SM FOR ACTUATING THE DIPPEROF A POWER-OPERATED APPARATUS `John P. Waite, Milwaukee, Wis., assignorto I. P. Waite, Inc., Milwaukee, Wis., a corporation of Wisconsin This invention relates to power operated excavating apparatus and more particularly to a mechanism for actuating the dipper of a back hoe.

In a conventional-type back hoe the dipper is generally actuated in the digging stroke by a cable which is attached to the forward portion of the dipper., ByV retrieving the cable the dipper is moved toward the machine and digs into the material to be excavated. vThe use of a cable such as this for actuating the dipper results in several di1liculties,in` that the cable frequently is dragged over the rough edge of the excavation thereby causing undue wear land abrasion on the cable. Secondly, due to the position of attachment of the cable to the dipper, it is difiicult to dig closely to the machine for the cable interferes with the digging stroke.

In addition, as the digging force is` dependent upon the combined weight of the dipper and the boom, this cable method of actuating the dipper tends to pull upwardly on the dipper so that the full weight of the members will not be utilized in the digging stroke.

The present invention is directed to a novel apparatus for actuating the dipperl and provides increased digging force over that obtainable by the conventional apparatus for actuating the dipper..

According to the invention the dipper stick which carries the dipper is pivotally attached to the outer end of a boom. The dipper stick and dipper are actuated by pushing outwardly on theA upper end of the dipper stick by means of a crowd rod. The'crowd rod is moved t0- ward the outer end of the boom by a sheaving and link` age arrangement which is powered by a drag cable pull.

With this construction therev is no cable orsheaving system attached directly tothe dipper-ina position where it might interfere with the digging action of the dipper. This results in the present back hoe being capable of digging closely beneath the machine vitself and also en- Patentedi Mar. 24,'1959 2 drag shovel comprising a cab 1 which houses the drive mechanism and is rotatable on crawlers or treads 2.

A boom 3 is pivotally connected between a pair of lugs 4 which extend upwardly from the forward portion of the cab 1 and a dipper stick 5 is pivotally attached to the boom adjacent the outer end thereof.

'I'he lower end of the dipper stick 5 is secured to the upper rear edge portion of a dipper 6 and a pair of pitch braces 7 interconnect the forward upper edge of the dipper and the central portion of dipper stick 5. The dipper stick 5, dipper 6 and pitch braces 7 are secured together in a xed relation to positively position the dipper with respect to the dipper stick.

The dipper 6 is of conventional construction and includes a pair of side plates 8 which are connected together by the generally curved bottom 9. The lower edge of the forward open end of the dipper is provided with a lip 10 which carries a plurality of teeth'll adapted to penetrate the material to be excavated. V

The boom 3 is raised and lowered by aconventional sheaving system. The sheaving system includes a sheave 12 Ywhich is rotatably secured between a pair of arms 13 that 'are connected to the upper end of the dipper stick 5. A second sheave 14 is journaled between a pair of braces 15 which extend'upwardly from the cab 1. A cable 16, which is secured to a drum 17, passes over sheaves 12 and 14 and is dead-ended on arms 13, as indicated by 18. By retrieving cable 16, sheave12 is moved toward sheave 14 thereby pivoting the boom' 3 upwardly about the forward portion of the cab, while letting out cable 16 serves to pivot the boom down#l wardly with respect to the cab.

According to the presentinvention, the dipper stick 5 is actuated by a sheave and linkage system associated wtih the boom and which is adapted to apply a force to l the upper end of the dipper stick to pivot the same about ables the dipper to undercut beneath pipes, boulders or the like without interference from cables.

For agi-ven pull on the drag cable the digging force of the dipper can be conveniently varied by changing the number and reeving of the sheaves. This also enables the speed of digging to be varied `for a given motor speed so that the motor can be driven at the most eiiicient speed, and yet the speed of digging may be varied as desired.

The drawings illustrate the best mode presently contemplated for carrying out the invention.

In the drawings:

Figure 1 is a diagrammatic side elevation of the back hoe of the present invention;

Fig. 2 is a fragmentary enlarged side elevation `of the boom embodying the present invention;

Fig. 3 is a vertical section taken on line 3-3 of Fig. 2; and

Fig. 4 is a diagrammatic showing of the reeving of the sheaves.

The drawings illustrate a power operated back hoe or the boom. This system includes a pair of armsV 19 which are pivotally connected to the upper end of the dipper stick. The inner ends of the arms 19 are pivotally atf tached to a pair of plates 20, located between the sideV walls of the boom, by means of a pin 21. I

To enable the plates 20 to move longitudinally with respect to the boom 3, a plurality of rollers 22 are rotatably secured to the outer surface of each of the plates 20. The rollers 22 are adapted to ride on a series of railsl 23 lwhich are secured to the inner surface of the sidey walls of the boom 3 and extend longitudinally of the boom. To retain the rollers 22 in position on the rails, the rollers are provided with flanges 24 which engage, the inner surface of the rails. v

A sheaving arrangement is employed to move the plates 20 along theboom and thereby apply a force through arms 19 to the upper end of the dipper stick to pivot the same. The sheaving arrangement includes a pair of sheaves 25 which are rotatably secured to a shaft 26 extending between the plates 20. A second pair of sheaves 27 are rotatably secured on a shaft 28 which connects the side Walls of the boom 3. The sheaves 25, being attached to the plates 20, are adapted to move relatively to the boom 3 and to the xed sheaves 27.

A cable 29, contained on a drum 30, passes between a pair of guide sheaves 31 and 32 which are connected to the boom and is reeved about the sheaves 25 and 27, as best shown in Fig. 4. The cable is dead-ended on boom 3, as indicated by 33. With this arrangement, a pull on the cable 29 results in the sheaves 25 and plates 20 being moved outwardly of the boom toward the ixed sheaves 27. Outward movement of the plates 20 exerts an outward force through arms 19 on the upper end of the dipper stick 5 to pivot the dipper stick 5 about the boom 3 and move the dipper inwardly toward the cab l..`

As the boom is elevated for the dumping operation by retrieving cable 16, cable 29 is let out, causing plates 20 to move inwardly with respect to the boom and thereby pivot the dipper stick 5 and dipper 6` upwardly with respect to the boom to dump the excavated material from the dipper While the description is directed to a pair of sheaves 25 and a pair of sheaves 27, it is contemplated that any number of sheaves may be employed and the reeving of the sheaves can be varied to obtain any desired mechanical advantage. By increasing the number of sheaves and the reeving thereon lthe digging force of the dipper can be increased and the speed of digging decreased, and conversely, by reducing the number of sheaves and the reeving, the digging force of the dipper can be reduced and the speed correspondingly increased. This construction enables the speed of digging to be conveniently varied for a given motor speed so that the motor can be driven at its most eicient speed and yet the speed and force of the digging may be varied as desired.

The present invention actuates the dipper by a force' applied to the upper end of the dipper stick. With this construction the cables, which are normally attached to the dipper of the back hoe to movethe dipper, are relocated. This enables the present back hoe to dig more closely beneath the machine, as there is no danger of interference with the drag cable during digging. Furthermore, the relocation of the drag cable enables the dipper to dig and undercut in locations which were heretofore inaccessible to a conventional back hoe due to the interference from the drag cable.

' By applyingv the force to the upper end of the dipper stick, rather than pulling upwardly on the dipper, a more effective use of the weight of the members is utilized in the digging operation.

Various modes of carrying out the invention are contemplated as within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

l. In a cablel operated back hoe, a supporting structure, a boom having one end portion thereof pivotally connected' to the supporting structure, a dipper stick pivotally attached at a position intermediate the ends thereofto the other end portion of the boom, a dipper secured to the lower portion of the dipper stick and adapted to penetrate into the material to be excavated, a cable secured to the supporting structure, a xed guide member secured to the boom and carrying said cable, a second guide member associated with the boom and carrying said cable, said second guide member being slidable with respect to said boom in a direction toward and away from said rst guide member, and an actuating member interconnecting said second guide member and the upper end portion of the dipper stick, said actuating member exerting a force on said dipper stick to pivot the same about the boom as said second guide member' is moved in relation to said iirst guide member.

2. In a cable operated back hoe excavator, a supporting structure, a boom having one end portion thereof pivotally connected to the supporting structure, a dipper stick pivotally attached at the central portion thereof to the outer end portion of the boom, a dipper secured to the lower portion of the dipper stick and adapted to penetrate into the material to be excavated, a plurality of cable guide members' xedly secured to the boom, a slide member slidably mounted on said boom and disposed inwardly of said rst cable guide members, a plurality of second cable guide members mounted on said slide member, an arm interconnecting said slide member and the upper end portion ofthe dipper stick, a cable securedto the supporting structure and reeved about said first and second cable guide members, means to exert a force on the cable member whereby the force serves to move said slide member along the boom and moves saidv second cableI guide members toward said rst cable guide members to move said arm outwardly against the upper end of the dipper stick to pivot the same with respectto the boom, and power operated cable means for pivoting thev boom in relation to the supporting structure.

3. In a cable operated back hoe, a supportingr struc'- ture, a boom pivotally connected to the supportingstructure` for pivotal movement, a dipper stick having the central portionthereof pivotally connected to theother end portion of the boom for pivotal movement, a dipper secured to the lower end portion of the dipper stick and adapted to penetrate into the material to be excavated, a plurality of cable guide members tixedly connected to the boom, a plurality of second cable guide members disposed inwardlytoward the supporting structure from said first cable guide members and slidably mounted on the boom, connecting means interconnecting said second cable guide members and the upper end portion of the dipper stick, a cable secured to the supporting structure and reevedv about said first and secondcable guide members whereby a change in the reeving of said first and second cable guide members will change the speed and force of the digging operation,` means to exert a force on the cable whereby the force serves to move said second guide members toward said first guide members to move said connecting means against the upper end of the dipper stick to pivot the same with respect to the boom, and separate power operated cable means connected to the upper end portion of the dipper stick for pivoting the boom in relation to the supporting structure.

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